Supporting and elevating mechanism for dental chairs.



No. 663,l43. Patented Deb. 4, 1900,

B. m. wiLm-znsou; SUPPORTING AND ELEYATING MECHANISM FOR DENTAL CHMRS (Application filed Nov. 535, 1898.) (No Modal.)

l5 sham-sum 1.

WITNESSES Patented Dec. 4, I900. B. M. WILKEBSUN. 8UPPORTING AND ELEVATING MECHANISM FOR DENTAL CHAIRS.

(M Model.)

(Applistion filed Nov. 25, 1898.)

I5 Sheds-Sheet 2.

NORMAL N0. 663,!43. Patnted Dec. 4, I900. B. M. WILKERSDN. SUPPGRHNG AND E LEVATING MEQHANISM FOR DENTAL CHAIRS.

(Application filed Nov. 25, 1898.) (M Modai.) I5 Sheets-Sheet 3.

JNVENTOR:

SUPPDBT'NG AND EL gab Model.) I

WITNESSES:

Patented Dem 4, i908. B. M. WILKERSGN.

EVATNG MECHAMSM FOR DENTAL CHAIRS.

(Application filed Nov. 25, 1898.)

I5 Sheets-Sheet 4.

g m igg/ENTCR: W, M,

No. 663,l43. Patented Dec. 4, I996. B. M. WILKERSON.

SUPPORTING AND ELEVATING MECHAMSM FOR DENTAL CHMRS.

(Application filed Nov. 25, 1898.} (No Model.) l5 Sheets-Sheet 5.

iNVENTOR: F $1 m 663,!43. Patented Dec. 4, lane.

8. M. WELKEBSGN. SUPPfiBTlfiG MED ELEVATING MECHAMSM FOR DENTAL CHAIRS. (Application filed Nov. 25, 1898.) (E40 Eflodei.) l5 Sheets-Sheet 6.

INVENTOR:

w NMNR WiTNESSES: M M

m. 663,143. Patented Dec. 4; I900.

a. m. wuxsasou. v

SUPPDBTING AND ELEVATING MECHANISM FOR DENTAL CHAIRS.

(Application filed Nov. 25, 1898.)

I5 Sheets-Sheet 7,

(No Made!) \I'WTNESSES: INVENTOR: $51M Ema gddw 2M mTQ/LJWA No. 663,543. Patented Dec. 4, I900.

B. M. WILKERSUN.

SUPPORTING AND ELEVATING MECHANISM FOR DENTAL CHAIRS.

l5 Sheets-Sheet 3.

(Application filed Nov. 25, 1898.) (No Model.)

WITNESSES:

No. 663,i43. v Patentafl Dec. 4, 29%. B. M. WILKERSUN.

SUPPORTING AND ELEVATING MECHANISMFOR DENTAL CHAIRS.

(Application filgd Nov. 25, 1898.)

(No Model.) I5 sheeis -sheet 9" FIG. 3

Patented Dec. 4, I900.

B.' M. WILKERSHN. SUPPORTING AND ELEVATING MECHANISM FOR DENTAL CHAIRS. (Application filed Nov. 25, 1898.! (No kiodal.) I5 Sheets8heet In.

F "Walk m. 663,!43. -P atented Dec. 4, 1900. B. m. WILKERSON.

SUPPORTING AND ELEVATING MECHANISM FOR DENTAL CHAIRS.

(Application filed Nov. 25, 1898.)

I5 Sheets-Sheet ll.

WITNESSES: /%,VENTOR:

Patentd Dec. 4, 900.

I B. M. WILKERSON.

SUPPORTING AND ELEVATINGMEBHANISM FOR DENTAL CHAIRS.

,(Application filed Nov. 25, 1898.)

I5 Sheehi-Sheet I2.

(No Model.)

FIG. 16.

INVENTQR. gm hi. wawfl b;

4 all mgr No. 663,I43. Patented Dec. 4, I900.

B. III. WILKERSON. SUPPORTING AND ELEVATING MECHANISM FOR DENTAL CHAIRS.

- (Application filed Nov. 25, 1898.) (No Model.) I I5 Sheets-Sheet l3.

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Patented Dec. 4, i900.

B. M. WILKERSON.

SUPPORTKNG AND ELEVATING MECHANISM FOR DENTAL CHAIRS.

(Application filed Nov. 25, 1898,] (No Model.) l5 Sheets-Sheet l4.

WITNESSES:

No. 663,l43.

Patented Dec. 4, I900. B. M. WILKERSON.

SUPPORTING AND-ELEVATING MECHANISM FOR DENTAL CHAIRS.

Sheet l5,

l5 Sheets (Application filed Nov. 25, 1898.)

'thesection being taken on the line 6 (3 of Fig.

. UNITED STATES BASIL M. XVILKFR ON, OF EALTTUORE WHITE DEN AL MANUFACTURING SYLVANIA.

PATENT OFFICE.

MARYLAND, ASSIGNOR TO THE S. S. COMPANY, OFPIIILADEL'PI'IIA, PENN- SUPPORTlNG AND ELEVATING MECHANISM FORDENTAL CHAIRS.

SPECIFICATION forming part of Letters Patent N 0. 663,143, dated December 4, 19.00. Application filed November 25, 1893- Serial No. 697.344. No 111011 1,;

To all whom, it may concern.-

Be it known that I, BASIL M. \VILKERSON, a citizen of the United States, residing in the city of Baltimore, in the State of Maryland, have invented certain new and useful Improvement-s in Supporting and Elevating Mechanism for Dental Chairs; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to supporting and elevating mechanism for dental chairs; and it consists in certain in'iprovements, which will be hereinafter claimed.

My-presentimprovcments compriseadeutal chair base of novel construction in which are contained four distinct mechanisms which may be operated orcontrolled by a single footactuated operating lever. 'lhesc mechanisms are, first, horizontal rotating mechanism comprising means for looking the chairbody in any position to which it may be horizontally adjusted; second, elevating mechanism; third, mechanism for clamping the vertically-adjustable chair-body-supporting plunger, and, fourth, lowering mechanism. In addition to the'base and the said mechanisms my invention also comprises a novel telescopic chairbody-supporting plunger and certain details of construction, all of which will be hereinafter fully described.

The accompanying drawings, in which similar letters refer to corres 'ionding parts throughout the different views, represent a suitable embodiment of my improvements.

Figure l is a view in side elevation of the chair complete. Fig. 2 is a top or plan view of the base portion of the chair with the chain body omitted. Fig. 3 isa vertical central sectional view of the base portion of the chair on the line 3 3 of Fig. 5. Fig. 4 is a similar view on the line 4 4 of Fig. 5, some parts beingin side elevation. Fig. 5 is a top or plan view of the base portion of thc'chair with some parts shown in horizontal section on the line 5 5 of Fig. 3. Fig. 6 is a similar view,

3 and with the operating-lever shown in its normal position. Fig. 7.is-a similar view on the same sectional line, but with the parts in dilferent positions, the operating-lever being in its position for elevating. Fig. Sis asimilar view on the line 8 S of Fig. 3, the operating-lever being shown in full linesin its elevating position and in dotted lines in its other positions. Fig. 1') is a milar view on the line 9 9 of said Fig. Fig. 10 is a vertical sectional view, drawn on the line 1O 10 of Fig.

7, of the rotary supporting frame or casting 6 0 and the pedestal or base with the supporting and elevating mechanism omitted, and particularly showing'the locking mechanism between said rotary supporting-frame and said pedestal. Fig. 11 is a horizontal section on the line 11 110E Fig. 10. Fig. 12 is a vertical section on the line 12 12 of Fig. 11, and Fig.

13 is a side elevation of the upper end ofthe clamp-rod and its bell-crank lever. Fig. 14:

is a view in side elevation of the rotary sup- 7o porting-fr? me detached, and Fig. 15 is a vertical section of the same on the line 15 15 of Fig. 8. Fig. 16 is a vertical central sectional view on the line 3 3 of Figs. 2 and ot the telescopic supporting and elevating mechanism, the supporting-frame and pedestal being omitted. Fig. 17 is a horizontal section on the line l7 17 of Fig. 16. Fig. 18 is a sec tion through one member of the telescopic. elevating mechanism on the line 18 18 of Fig. 16, and Fig. 19 is an inverted plan view of the lower end of said member. Fig. 20

is a view in side elevation of the guide-cylinder of the supporting and elevating mech anism; and Fig. 21 is a similar view of the same, showing it turned at a right angle. Fig. 22 is a central vertical sectional view of said cylinder on the line 22 32 of Fig. 23. Fig.- 23 is a plan or top view of said cylinder. Figrfli is a cross-section of the same on the line 2-1 2i 0!" Fig. 21, and Fig. 25 is a crossscction thereof on the line 25 25 of Fig. 22. Fig. 2(iis a top or plan view of the pump, its supportirig-casting, and valves. Fig. 27

is a vertical section of the same on the line 27 27 oi Fig. 26. Fig. 28 isa sectional diagram matic view of the pump, valves, and plunger cylinder, the section being drawn on the lines 27 28. Figs. 29 to 33, inclusive, .Shecto, are separate views of the various parts 10 of the telescopic plunger-clamping mechanism. Fig. 34 is a plan or top view of the main i-operatihg-lever detached. Fig. 35 is a view -in side elevation of the same. Fig, '36 is a section of the same on theline 36 36 of Figs.

4 and 35,and Fig. 37 is a section on the line 73.7 of Fig.34. Base.'-The term base used throughout he specification and. claims designates a 01 1 comprising a'stationary or non-roble ped estal, as B, a rotatable .sup,portframe',,,a s A, and a detachable cap or s B (See particularly Figs. 1, 3, i,

' nd ,15.;)j;-: The, pedestal B,'as shown,

liquid-reservoir of the base and is also y" 'rovidedwithan annular cr -disk 1e orjf'rest'ing upon ithe noon, Boy'fitted in said pedestal B is thelfsup ameor casting A, which supports he entire chair-body supporting ndeleva ng mechanisma" The supporting eie;(seperti u ly is 'l ons'ists "of adopter or 'main cylindrical secion A and anfinn erlcylindrical section A,

" Q,sa id: .outer cylinden and which ve the top of the same. The outer ylind cals'ec tion A of the supportingframe formed ts .upper end with an annular flange a liich rests and turns upont'he up-' '1' end of the pedestal B and hafs near its d'bot'tom bearing-surfaces a a ,-which I against"cprresponding surfaces on the interior of the pedestal. By this construction'the supporting-frame is supported withinthepedestal and may be freely rotated dah'erein to provide for the horizontal turning movement or'adj'ustment of the chair-body,

which, as before stated, '5 supported by way,

of saidsupporting-frame. The two cylindrical sections A and A of the supporting-frame are connected by means of vertical webs a and a horizontal web or plate ct. (See Figs. 9, l0, and 15.) The purpose of the horizontal web or plate a! is mainly to hold the respective sections of the supporting-frame together and to strengthen the entire structure; but it also admirably servesas a floor orbase for aportion of the elevating and lowering mechanism and pro- 'tects the oil in the reservoir from any foreign matter that may fall into the base when the upper end of' the same is exposed.

A detachable cap or don1e B forming part of the base and preferably made in two se'ctions, (see Figs.. 1,2, 3, and 4,) is suit-ably fitted upon the supporting-frame in suclr a way as to cover the space between the sections of said supportingirame, thus complctely iuclosing the mechanism contained in the'base. Thelowerend of the cap restsupon the upper end of the outer cylinder Aof the supporting-frame, while the upper end. of said cap surrounds the inner section A of said framejust below an exterior flange or annular shoulder (1 thereon, and the sections of the cap may be bolted tqgethcr in any suitdedlwith aelosed bottom B and serves;

tions of the cap are removed the entire mechariisms contained in the base are exposed to view and while thus exposed may be freely operated. When the cap is thus-removed, the horizontal web or plate a',as before stated sef'vsf to prevent foreign matter from falling into the oil inqtherescrvoir beneath said web,

- Y StlgJportt'ng-fi'aine-locking mechanism-Inorder to lockihe chair-body in any position "to vwhich it may be horizontally rotated and to preventit from being accidentally turned, I have provided suitable locking mechanism be tween the rotatable su pporting-frame and the non-rotatable pedestal. This locking mechanism (see Figs. 10,11, 12, and 13) may consist of a vertical rod A mounted to turn in bearings a and a inside the supportingframe, and means actuated by the turning of said rod for frictional] y engaging the pedestal to lock the supper! ing-frame thereto. In the present instance I have shown this means as consistitgof a clam p blocker shoe A adapted to slide horizontallyin a hearing in said supporting-frame and in a notch or recess 07 in the rod A near the lower end thereof, the outer surface of said block corresponding to the curvature of the bearing-surface of the pedestal, between the same and the lower end of the supporting-frame. Theinner surface of the'clamp-block is also curved and is borne upon by a flattened or cam-surface a on the rod A formed by the inn'er wall of the recess a". When the rod A is turned in one dir''ctiom'its flattened or cam surfaceforces thfe clamp-blocktightly against the pedestal and securely locks the rotatable supporting-- frame to the non-rotatable pedestal, thus preventing rotation of the chair bod y. If desired, a light plate-spring of may be secured at a to the outside of the supporting-frame 'and fitted ina groove in the outer or hearing surface ofthe clamp-block to hold the same in place when the su pporting frame isremoved from the pedestal, while not interfering with the .free movement of said block. To the top of the rod A is attached a bell-crank lever A, (see Figs. 6 and 13,) to one arm of which is secured a coiled wirespring A which acts upon the lever with a tendency to turn the red A in a direction to force the clamp-block against the pedestal, as just described, this being the normal positiouof the rod. The manner of turning the rod for leaving the supporting-frame free to be rotated will be' explained hereinafterzvObviously various forms-of clamping or 1 cking devices other than the particular clahp-block may be used in lieu thereofj Chair body support/i 1g plunger. The

-inecl1a n-ism for supporting the chair-body and by whichthe same may be raised and lowered ICC is as follows, (see Figs. 3, 4', 6, and 15 to 25, inclusive Rigidly connected to the supporting-frame A is an upright cylinder A, which will hereinafter be designated the fixed plungercylinder. This plunger-cylinder is shown as having screw-threaded connect-ion with a socket-piece A at the lower end of the inner section A of the supporting-frame For convenience of manufacture I prefer to make the lower portion A of the inner section A of the supporting-frame separate and connect it to said frame by means of screws (/1 (See 3 and 15.) The socket-piece A" may be cast integral with the lower portion A" of the inner section A of the supporting-frame, and it closes the lower end of the fixed plunger-cylinder A. It is shown as being held in place by means of webs a (Best shown in Fig. 26.)

Fitted in the fixed plunger-cylinder A and movable up and down therein is the cy1indrlcal member A of the vertically-movable ftelescopic chair-body-supporting plunger. A

guide-cylinder A is rigidly connected to the upper end of and moves with the cylindrical member A of the telescopic plunger and surrounds and is adapted to move up anddown upon the fixed plunger'cylinder A and also has bearing in the inner cylindrical section A of the supporting-frame A. Notches a (see Figs. 21, 22,.and 24:) are formed in the lower end of the guide-cylinder A and straddle the webs a of the socket-piece A when said cylinder is in its lowest position, so that said webs do not interfere with the full descent of the guide-cylinder.

The piston member A. of the telescopic supporting-plunger, upon which member the chair-body is mounted, ashereinafter explained, is preferably solid and is fitted to be moved up and down in the cylindrical member A of the plunger and also has bearing in the guide-cylinder A at and near-the top thereof. Suitable packing (1 is provided at the top of the fixed plunger-cylinder A for making a liquid-tight connection between the inside of this cylinder and the cylindrical member A of the telescopic plunge-r. The lower end of the piston member A of the plunger is also provided with suitable packing a for making it liquid-tight in the cylindrical member-A c... the, plunger. I prefer that this piston-packing be constructed as followsi The cup-shaped leather packing a is flexible and is held in placesome distance from the lower end of thepiston by means pl a metallic head A, the same diameter as ,the piston, and secured thereto by S(5l'6W3 (L An annular groove or channel a is cu t in the metallic head A of the piston behin the leather packing adjacent to and openii .5 into the groove in the metallic head in whichthe packing is fitted. A vertical port a is made in the metallic head and leads a into the channel (L27.

ber of the plunger is being elevated and also When the piston memwhen it is descending, the oil in the plungercylinder under pressure beneath the piston is forced through the port a into the channel 00 and the cup-shaped packing is expanded against the cylindrical member A of the telescopic plunger, whereby the proper close contact of the );t(l(lllf,{ with said cylider is insured.

In order to relieve the chair from all jar and shock when the chair-body-supporting plunger reaches the extreme of its up and down movements, I have provided said plunger with suitable huliing devices, which will effectually cushion the plunger at the end of its upward movement as well as at the end of its downward movement.

Referring to'Figs. 3, 16, and 19, it will be seen that the lower end of the piston member A of the telescopic supporting-plunger is bored out centrally to form an oil-chamber e, and a buffer-rod or plunger E is fitted to reciprocate in said chamber. 'Said buffer-rod is held in place by means of a screw-plug E closing the lower end of theoil-cham'ber c, the stem of the rod passing through a central opening in said screw-plug and the head of the rod abutting against said plug when the rod is in its lowest. position. A spiral spring E isconfined in the oil-chamber e, between the upper end thereof and the head of the bufferrod, and serves to cause the butter-rod to project beyond the lower end of the piston. The screw-plug E is formed with small holes e, and the diameter of the head of the bufferrod is slightly smaller than the oil-chamber of the piston in order that oil may pass between the plungen-cylindei' and the oil-chamber e, or channels or grooves may be cut in the head of the buffer-rod for this purpose.

When the piston is in an elevated position relatively to the bottom of the plunger-cylinder A, the spring E forces the buffer-rod downward and the oil-chamber is filled with oil, which enters through the openings e in the screw-plug E and passes through or around the head of the buffer-rod. When the pistondescends just before the end of its downstroke, the buffer-rod strikes the bottom of the plunger-cylinder and is forced upward against the stress of the spring E and the oil in the chamber above the buffer-rod escapes back to the plunger-cylinder by way of the space between the head of the butterrod and the walls of the chamber and the openings e. The oil escapes from the oilchamber very slowly and affords a cushion for the butler-rod, which thereby cushions the hnal movement of the piston and relieves the chair from all jar or shock in its descent.

Referring now to Figs. 21 and 22, one of the notches a in the lower end of the guide cylinder A of the telescopic supporting-plunger is provided with a coiled spring 0 which is seated in' a socket opening into the top of said notch, the spring projecting into said socket. When in the descent of the chairbody the guide-cylinder A reaches its lowest 71897. Ido not position, the spring 2 the webs a and acts as a buffer to relieve said guide-cylinderfrom jar.

The upward movement of the piston member A of the telescopic supporting-plunger is limited by a shoulder (1, formed by the lower end of a longitudinal groove a in said piston member coming'in contact with a stop on the upper end of the guide-cylinder A This stop is shoe C farther (See Fig. 3 or 16.) Secured upon the lower edge of said clampblock is a plate-spring E which normally stands off from said clamp-block, and when said piston reaches. the limit of its upward of striking movement in the guide-cylinder A instead directly against the clamp-block or whatever stop maybe used the shoulder a is met by said spring E and the piston is thus relieved of shock or jar.

A suitable stoplug formed bya screw 01. (see Figs. to 25, inclusive) is placed on the outside of the guide-cylinder -'A", near the bottom thereof, andser-ves to limit the upward movement of saidguide-cylinder by coming in contact with the upper end of the inner'section A of the supporting-frame. A

spring (not shown) similar to the spring E should be provided for cushiouingthe guide qfylinder when it reaches the limit/of its upward movement. In this way not. only 'is the telescopic supporting-plunger cushioned at upward and downward moyethe ends of its ments, but the members or sections of the plunger are likewise cushioned at the ends of their movements. In other words, all the movable parts: of. the supporting-plunger whichare adapted to strike other parts are cushioned, whereby the operation of-the supporting mechanism is noiseless and without shock or jar.

The upper end of the guide-cylinder A i may be beveled off to form a trough-like depression (1 around the pistonjyA, adapted to catch any oil that may be carried up by v or channel 06 the reception of any said piston and which runs down therefrom. The oil which collects in "this depression may escape therefrom by way of the groove a in the piston and a hole 0 in the before mem tioned clamp-block C If desired, a pocket may be formed in the guidethe telescopic plunger.

Plunger-clamping mechanism. -The in echianism for clamping the sections or members of thetelescopic chair-body-supporting plun- "-ger togetherand for simultaneously clam ping I the chair-body the plunger: as a whole to the supportingpurpose of firmly supporting frame for the against vibration or shaking movement'is in some respects similar to the mechanism shown, described, and claimed in my Patent No. 581,670, granted April 27,

wish to be understood as strikes against one of.

'20, 22, and 25.) The innersurfa .o

adjusted. The inner member 0 in said patent.

The plunger-clamping mechan'ismlisbest illustrated in Figs. 3, 5, 6, '7, 16,-1Z,;2Qlft and 29 to 33, Sheet 5, and in the presen stance is shown as consisting of a Gamma-35- C, arranged parallel with the nected thereto fear the top andfbottom by screws 0 c and a dowel-pin c fa(.See; Eigs. ,5,

is curvedtransversely to correspon outer surface-of said guide-.cylind is provided 'o'njsaid inner'surface gitudinal projection or rib fcQfwhi guide-cylinder A of' the telescopic plunger and-looselyacom' insbar I against said guide-cylinder ina'longitudinal.

groove (1 therein, the clamp barfbeing'adapte ed to have a slight horizontal rocking movement on said rib c as a fulcrumg' Afclamp' blocker shoe 0? is fittedto slide horizontallyin a bearing in'the guide-cylinder A thevinner end of this block projecting intofaflon'gitud' nalgroove a in the'solid'piston member-A of the telescopic plunger and'is borne upon-by the clamp-bar O; The front rounded edge of one memberO of a toggle-lever bears i'nal'ongitudinal groovec on the outer. surface of the clamp-bar O and the outer memberC oE the] toggle-lever'has bearing in an adj iistable ful c'rum-pieceC (SeeFigs.'3and 5.) Theadjustable fulcrum-piece O is provided with a rou nd shank 0 which passes through a long tubular nut'O, screwing into an extension A of the supporting-frame section A, this extension also serving to accommodate the clampbarO and its operating toggle-lever. That .partof the long nut O which projects outside of the supporting-frameextension A is provided with wrench-engaging surfacesOfl; and a jam-nut O ldng nut in any position to which it maybe of the 1:0,,- gle-lever is formed with two lug's'c c and a space a between the lugs, and the outer memberC of the toggle-lever is formed with a cut-away or beveled portion 0?, on which isa lug 0 adapted to register withthe space-c of the member 0. (See Figs. Band 29 to 33;) This formation provides a vef'y'strong-toggle-lever without interfering with its free movement. The outer .memher Ciqis. extended some distance below the innermeinher and on its lower end is formed with alug 07, which slides in agroove c in the top'fof a lever 0 Said lever is provided withjapintle 0 having bearing in a socketon thesupporting-frame, the lever turningeii, -t is pintle as a fulcrum. The socket or bearing for the pintle of the lever C is shown. as being formed in a block A, secured to the outside of the cylinder A screws 0 (See Figs. 3 and 14.) An adjustable bearing maybe provided for the top of the outer memberdc of the toggle-lever and is shown as consisting of a screw O is employed for locking the of the supporting-frame-by and force the clamp-bar C inward against the block or shoe with snfficient force to clamp the piston member A of the telescopic V plunger in the guide-cylinder A thereof and at the same time bind or clam p the saidgu idocylinder A in the inner cylindrical section A of the supporting-frame. lhe lever C is also provided with a long arm (1, by which the lever may be rocked against the stress of the spring A to bend or flex the toggledeverand uuelamp the telescopic plunger. It will thus be seen that-the plunger-clamping mechunisut normally acts to clamp the sect-ions or member of the telescopic plunger together.

and the plunger as a whole to the supportingframe, whereby the chair-body is rigidly supported against lateral vibration, that when, the lever C is actuated to overcome the action of the spring A as will be hereinafter described, the toggle-lever simultaneously unclam ps the clam p-bar G and shoe O ,whereby the gutde'cytmderA, carrylng with it'the clam p-bar (his free to be moved up and down in the su pportin g-frame,and the piston-section A of the plunger is free to be moved up and down in the guide-cylindeaand that when the lever C": is actuated to come within the influent-e of the spring the toggle'lever automaticallyaets to simultaneously clamp the members oi the plunger together and to the sup porting-frame in whatever position of vertical adjustment the plunger members may oceupy relatively to each other or to the supporting-frame.

The togglelever may be adjusted to exert more or less force against the clamp-bar C by means of .the adjusting-nut C the member C of the toggle-leverfireely sliding in or out in the groove 0 of the lever C withoutdisturbing the pivotal connection between the toggledever and the supporting-frame, which connection is by way of the pintle C of the lever 0 Y 1 It should be understood that portions of my im proved plunger-clamping mechan ismsuch, for instance, as the tog-gle-leverare not confined to telescopic plungers, but are applicable to simple or non-telescopic plun- Elerali'ng and lowering m cchanism.The

previously describedv telescopic chai r-body supporting plunger is adapted to be raised and lowered for the purpose of varying the vertical position or adjustment of the chairbody supported thereby by means,preferably, of hydraulic elevating and lowering medianisms, as next to be described. 5), :26, 27, and 28.)

The pump for imparting an upward move- (See B igs. 4,.

ment. to the telescopic plunger and the valves for eont.rolliu; the flow ol oil between the oilreservoir formed by the pedestal l3 and the pump and between the pump and the tixecl plunger-cylinder A"are preferably carried by a single ca ting I), having detachable connection with the supporting-frame A.

The vertical pump-cylinder D' is shown as made in a separate piece having screwthreaded connection at its lowcrend atll with a socket or opening D in the casting D, or, if preferred, the pump cylinder may be cast integral with the said casting I). An oilinlet valve D seated in a screw-plug D", which closes the lower end of the socket or opening D in the casting, serves to admit oil from the oil-reservoir to the pump-cylinder through an opening (1' inthel scre\\'-plug D when the pump-piston D is raised and to prevent the return of oil to the reservoir when said piston is depressed. A port or passage-way d in a portion of the casting I) communicates with a chamber (1 in the casting and through which all oil from the pumpcylinder to the plunger-cylinder and from the plunger-cylinder to the oilreservoir must pass. The upper end of this chamber (1 is closed bya plug D screwed into the casting and forming a seat for an outlet-valve D and a bearing for the stem (1 of said outlet-valve. (See Fig. 27.) The outlet-valve l) is formed with adownwardlyextending tubular projection (1 which constitutes a bearing and guide for the stem (1 of a check-valve D adapted toclose the' port or passage-way:(l between the chamber (1 and the pump-cylin- Vder for preventing the return of oil to said pump-cylinder fronrthe plungen-cylinder. The stem of the check-valve D it will be seen, slides in the tubular bearingd of the outletvalve and automatically closes the passageway d by virtue of a spring d surrounding the stem of the valve D and bearing at its opposite ends against the valve D and the projection d of the outlet-valve, this I spring also serving to normally close the outlet-valve. longitudinally corrugated, grooved, or flattened at one or more places on its sides, as at (i to permit oil to pass from the chamber (2 to the oil-reservoir when the outlet-valve is tripped to lower the chainbod y. The upper end of the outlet-valve stem projects above the plug D, and has fitted upon it a cap D", having an outer annular flange (1", which loosely surrounds the outside of the upper end of the plug D,with aspaee between said flange and said plug. The function of the flanged cap D" is to deflect downwardly the oil escaping from the plungencylinder by way of The outlet-valve may be tripped or opened for lowering the ch air-bod y by applying down- The stem at of the outlet-valve is 

